In the SQL Server DBA Interview, questions related to wait types are prevalent. In this post, I am sharing a small note on few important wait types those you guys can use in your replies.

You can use below query to check the different waits in SQL Server

select *from sys.dm_os_wait_stats

Important wait types:

ASYNC_NETWORK_IO: Network related waits, which causes by a client application that is not processing results from the SQL Server

LCK_M_IX: Occurs when a thread is waiting for a table or page IX lock so that a record insert or update can happen

LCK_M_X: Occurs when issue of lock escalation happens

CXPACKET: Issue in Parallel query execution, indicates that SPID is waiting for parallel processing

PAGEIOLATCH_SH: Occurs when data page is waiting to be read into memory

OLEDB: When SPID is waiting for remote procedure calls from OLEDB linked server

SOS_SCHEDULER_YIELD: When high CPU usage occurs

WRITELOG: Waiting to write the contents of the log cache to disk